Electric lamp fittings and other powered appliances are in common use across the world in both domestic and industrial/commercial situations.
Industrial lamp fittings and other powered appliances used in industrial situations such as instrumentation, electric motors, control valves, junction boxes and process instrumentation and the like may be large and heavy and mounted inconveniently for maintenance because of being mounted at height or present in a dangerous environment. Such lamps and other appliances may be mounted to a spigot at the end of a pole or on a proprietary bracket.
Due to conditions present at various industrial sites maintenance of lamps and other electrical appliances often presents difficulties. For example, control valves, junction boxes and process instrumentation need to be removed for maintenance, inspection or repair as in situ operations are either onerous for the worker or not allowed due to safety considerations. Similarly in the case of light fittings, the light fitting needs to be removed from the mounting or disassembled, maintenance work carried out and the light fitting reassembled, if necessary and then secured back to the mounting in one operation. As specialized lifting equipment is generally required to gain access to such lights and other appliances, these maintenance operations are carried out by the maintenance personnel on an elevated work platform, scissor lift, scaffold or other apparatus, which presents difficulties and may be expensive due to hourly hire rates applicable to such equipment. Similar difficulties arise in any situation in which work is carried out on location rather than in a workshop environment, for example, lights mounted on elevated walkways and other elevated points for example in mine sites. Further difficulties include interference with traffic or any other operations being conducted in the vicinity of the light fitting. For example whilst working at height the area has to be barricaded and traffic and personnel restrictions are put in place. Access equipment is charged out by the hour making most simple tasks such as changing a light globe expensive.
In addition to the above difficulties hazardous areas present an even greater challenge. Hazardous areas are classified as such due to the presence of gas, vapours, solvents, chemicals, dust, and any other combustible material being present in the work or plant environment. The restrictions placed upon workers carrying out maintenance in these areas are extremely high. At no point can a worker have live or powered terminals exposed to the atmosphere containing these combustible materials. Gas testing and monitoring must be carried out before and during any maintenance can commence. Basically to carry out any maintenance the worker must be able to completely isolate all power from the equipment being tested and worked on or have a mechanism that allows the equipment to be removed from the power supply prior to being dismantled and worked on.
All electrical equipment in hazardous areas must have periodic detailed inspections carried out on them (by law) As these are detailed inspections requiring all components of the equipment to be inspected, all power must be removed from the equipment so this may be carried out.
The time taken to carry out these inspections is substantial and extremely costly as the electricians must be specially trained to carry out these checks and maintenance.
The type of light fittings used in hazardous areas are big, bulky fittings. Added to this cost is the high maintenance aspect of the fittings.
Further, in order to constrain carbon emissions, control of electrically powered appliances is desirable. This may be in an attempt to decrease power consumption and/or to take into account varying power availability at certain times. As electricity generation becomes more decentralized and more power is derived from renewable sources the need to control such an appliance becomes more apparent at all levels: industrial, civic and private.
The present inventors developed an interest in inductively powering apparatus to attempt to address at least some of these issues.
A number of proposals have been put forward to power appliances in the lighting field and other fields including a family of related inventions by inventor Baarman and others such as US 20030201731, US 200030214255, US 20030214257, US 20040164686, US 2006 0284713, US 20070085487 and US 20100072826. The Baarman inventions concern inductively coupled power to devices mainly in the field of UV sterilization of water. US 20070085487, for example primarily relates to a ballast circuit but mentions an inductive coupling and refers to optical control of the shorting device for start up of the UV lamp.
WO 2001 016995 by inventor Haynes discloses a split transformer in which the secondary is attached to an illuminable item such as a drinks coaster or poker chip and the primary side is present on a table. The power supply is continuous and when the coaster or poker chip is placed on the table it lights up.
WO 2003 009653 by inventors Bucks and Nijhof relates to a power supply arrangement driving for a LED aimed at reducing EMI interference by a particular switching regime.
EP E0478306 Kakitani discloses an apparatus for providing stable DC power for a control circuit to operate a discharge lamp with a primary and secondary inductive winding.
DE202004014497U1 by inventor Yen discloses an inductively powered LED lamp for use in a water filled vessel with primary and secondary windings.
Other proposals using varied appliances have also been put forward. For example CN201535441 relates to a battery powered “intrinsically safe work lamp”, CN 201083345 discloses inductively rechargeable battery powered torch and CN 201263620 relates to an inductively powered lamp on a cordless kettle.
While particular proposals relating to lighting such as by inventors Limpkin and Rozenberg have been put forward, there are doubts about whether these would be practical for operating the appliance. For example WO2004/097866 appears to disclose a two part induction coupling linking an AC winding on a half core of a split transformer to a secondary winding connected to a load such as a lamp.
Yet other disclosures such as U.S. Pat. No. 6,188,179 by inventor Boys relate to a transformer for use with fluorescent lights in environments where arcing is undesirable. In this system a primary coil may be run around the cabin of a boat, for example and when light is required a fluorescent lamp attached to a C-shaped coil, acting as the secondary winding is hooked over the primary coil. The primary coil carries current in the order of 60 A requiring specialized fit out. While arguably this allows the connection/disconnection of the lamp without danger it does not provide a system which would be easily adapted to everyday use in homes, offices or industrial sites.
In a completely different field Japan Patent Application 2000-252145 by inventor Kuki Heiji discloses a two part induction connector in which there is optical communication between the primary and secondary sides. The connector is designed to be permanently incorporated in the door or of a van and allows powering of the windscreen wiper and indicator light upon opening and closing of the van door.
The above references to and descriptions of prior proposals or products are not intended to be, and are not to be construed as, statements or admissions of common general knowledge in the art.
The present invention attempts to overcome at least in part the aforementioned difficulties associated with operating, controlling and maintaining electrical appliances including industrial lamp fittings.